The present invention relates to RF coils for use in magnetic resonance studies, and more particularly inductively coupled RF coils for use in medical magnetic resonance imaging (MRI).
The quality of medical magnetic resonance images that an MRI system can produce is potentially limited by the performance of various system components, such as the gradient sub-system, the transmitter, the receiver pre-amplifier and other components. The radio frequency (RF) receiver coil is just such a system component which potentially can limit the image quality that can be realized by the particular MRI system.
RF coils must meet several requirements in order to insure satisfactory system performance. They must exhibit a high quality factor (Q-value) when they are unloaded and the Q-value must not become too diminished when the coil is inserted in the MRI scanner. On the other hand, the coil must couple well with the region of a patient's anatomy which is to be imaged, and this will result in a diminished Q-value. Ideally, an RF coil will exhibit a nearly uniform sensitivity throughout the region of interest to be imaged, and the coil sensitivity will be much lower outside the region of interest. The coil must also conform well with the anatomy being imaged.
It is therefore an object of the invention to provide an improved RF coil for medical magnetic resonance imaging which exhibits good localized sensitivity when placed on a patient and which can be conveniently fitted to various parts of a patient's anatomy.